1. Field of the Invention
The present invention relates to a reflective liquid crystal display device(LCD) and more particularly to a reflective plate having lightweight and a reflective LCD using the same.
2. Description of the Related Art
A Reflective LCD generally comprises upper and lower substrates opposite to each other, a liquid crystal layer interposed between the upper and lower substrates, a polarization plate formed at an outside of an upper substrate, and a reflective plate formed at an outside of the lower substrate.
A black matrix is formed on the upper substrate so as to define a sub-pixel and a color filter is formed in the space surrounded by the black matrix.
A switching device and a pixel electrode are formed at each sub-pixel of the lower substrate.
Such reflective LCD utilizes natural light instead of separate light source.
Consequently, when a natural light is entered from the upper substrate, it is reflected again by a reflective plate at a lower face of the lower substrate after passing the upper substrate, the liquid crystal layer, and the lower substrate. At this time, the light is absorbed or passed depending on an arranged condition of liquid crystal molecules.
The thickness of upper and lower glass substrates has been reduced in order to lighten the aforementioned conventional reflective LCD as well as most LCDs.
However, since the thickness of a substrate now reaches the limit and is not fully lightened, an art capable of replacing materials of a substrate is on study.
For example, an art using a plastic substrate lighter than glass instead of a glass substrate is proposed. This plastic substrate, however, is thermally, chemically, and mechanically damaged during a formation process of an array pattern and a formation process of a color filter thereby deteriorating the picture quality of an LCD.
Accordingly, it is an object of the present invention to provide a reflective plate having lightweight as well as functioning as a substrate.
Furthermore, it is another object of the present invention to provide a reflective LCD using a reflective plate with lightweight capable of improving the picture quality.
To accomplish the aforementioned objects of the present invention, a reflective plate of the present invention comprises: a plastic plate; a photoresist layer disposed on the plastic plate and having an uneven portion on the surface thereof; and a reflective film having a high reflectance coated on the photoresist layer having the uneven portion. Herein, the photoresist layer is a polycarbonate layer.
Moreover, the high reflective film further comprises: a planarization layer formed on the photoresist layer so as to planarize the surface of the photoresist layer; a transparent electrode disposed over the planarization layer; and an alignment layer formed over the transparent electrode.
Furthermore, the high reflective film further comprises: a planarization formed on the photoresist layer so as to planarize the surface of the phtoresist layer; an alignment layer disposed over the planarization layer; and a transparent electrode formed at the back side of the plastic substrate. The reflective film having a high reflectance is an aluminum layer.
And, a reflective LCD according to the present invention comprises: a transparent insulating substrate; a gate bus line and a data bus line formed at an inner side of the substrate and defining a pixel region; a pixel electrode formed in the pixel region; a switching device operating the pixel electrode by receiving the signals of the gate bus line and the data bus line; a black matrix formed on the surface of the substrate and covering a portion at which the gate bus line, the data bus line, and the switching device are formed; color filters respectively formed at the outsides of the black matrix; and a plastic reflective plate opposing to the inner side of the substrate. Herein, the plastic reflective plate comprises: a plastic plate; a photoresist layer disposed on the plastic plate and having an uneven portion on the surface thereof; a reflective film having a high reflectance coated on the photoresist layer having the uneven portion; a planarization layer formed on the photoresist layer so as to planarize the surface of the photoresist layer; a transparent electrode disposed over the planarization layer; and an alignment layer formed over the transparent electrode.
Further, a reflective LCD according to another embodiment of the present invention comprises: a transparent insulating substrate; a gate bus line and a data bus line formed at an inner side of the substrate and defining a pixel region; a pixel electrode formed in the pixel region; a switching device operating the pixel electrode by receiving the signals of the gate bus line and the data bus line; a black matrix formed on the surface of the insulating substrate and covering a portion at which the gate bus line, the data bus line, and the switching device are formed; color filters respectively formed at the outsides of the black matrix; and a plastic reflective plate opposing to the inner side of the insulating substrate. Herein, the plastic reflective plate comprises: a plastic plate; a photoresist layer disposed on the plastic plate and having an uneven portion on the surface thereof; a reflective film having a high reflectance coated on the photoresist layer having the uneven portion; a planarization layer formed on the photoresist layer so as to planarize the surface of the photoresist layer; an alignment layer disposed over the planarization layer; and a transparent electrode discharging static electricity at the back side of the plastic plate.